Aerosol separator; and method

ABSTRACT

An arrangement for separating a hydrophobic liquid phase from a gaseous stream includes a coalescer filter, a housing, a gas flow direction arrangement, and a liquid collection arrangement. The coalescer filter includes a non-woven media of fibers. The housing includes an interior having a gas flow inlet and a gas flow outlet. The liquid collection arrangement is positioned within the housing construction and is oriented for receiving liquid collected from the coalescer filter and drained therefrom. Methods for conducting the separations are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 09/010,098filed Jan. 21, 1998, now U.S. Pat. No. 6,171,355. Application Ser. No.09/010,098 is a continuation-in-part of application Ser. No. 08/884,294,filed Jun. 27, 1997, now U.S. Pat. No. 5,853,439. Application Ser. Nos.09/010,098 and 08/884,294 are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to systems and methods for separatinghydrophobic fluids (such as oils) which are entrained as aerosols, fromgas streams (for example, air streams). Preferred arrangements alsoprovide for filtration of other fine contaminants, for example carbonmaterial, from the gas streams. Methods for conducting the separationsare also provided.

BACKGROUND OF THE INVENTION

Certain gas streams, such as blow-by gases from diesel engines, carrysubstantial amounts of entrained oils therein, as aerosol. The majorityof the oil droplets within the aerosol are generally within the size of0.1-5.0 microns.

In addition, such gas streams also carry substantial amounts of finecontaminant, such as carbon contaminants. Such contaminants generallyhave an average particle size of about 0.5-3.0 microns.

In some systems, it is desirable to vent such gases to the atmosphere.In general, it is preferred that before the gases are vented to theatmosphere, they be cleaned of a substantial portion of the aerosoland/or organic particulate contaminants therein.

In other instances, it is desirable to direct the air or gas stream intoequipment. When such is the case, it may be desirable to separateaerosol and/or particulates from the stream during the circulation, inorder to provide such benefits as: reduced negative effects on thedownstream equipment; improved efficiency; recapture of otherwise lostoils; and/or to address environmental concerns.

A variety of efforts have been directed to the above types of concerns.The variables toward which improvements are desired generally concernthe following: (a) size/efficiency concerns; that is, a desire for goodefficiency of separation while at the same time avoidance of arequirement for a large separator system; (b) cost/efficiency; that is,a desire for good or high efficiency without the requirement ofsubstantially expensive systems; (c) versatility; that is, developmentof systems that can be adapted for a wide variety of applications anduses, without significant re-engineering; and, (d)cleanability/regeneratability; that is, development of systems which canbe readily cleaned (or regenerated) if such becomes desired, afterprolonged use.

SUMMARY OF THE INVENTION

An arrangement for separating a hydrophobic liquid phase from a gaseousstream comprises a coalescer filter, a housing construction, a gas flowdirection arrangement, and a liquid collection arrangement. Thecoalescer filter preferably comprises a non-woven media of fibers. Thehousing construction defines an interior and has a gas flow inlet and agas flow outlet. The gas flow direction arrangement is constructed andarranged to direct gas flow (for example crankcase blow-by gas flow)through the coalescer filter as the gas is directed into and through thehousing construction. The liquid collection arrangement is positionedwithin the housing construction and is oriented for receiving liquidcollected within the coalescer filter and drained therefrom.

Preferably, the coalescer filter comprises a panel constructionremovable from, and replaceable in, the arrangement.

Preferably, a liquid drain construction is in fluid communication withthe liquid collection arrangement. The liquid drain construction isconstructed and arranged to selectively drain collected hydrophobicliquid from the housing construction interior.

In certain preferred embodiments, the arrangement further includes asecond filter. Preferably, the second filter is positioned within thehousing construction and is located downstream from the coalescerfilter. The gas flow direction arrangement is constructed and arrangedto first direct gas flow through the coalescer filter and then tosecondly direct gas flow through the second filter, as gas is directedinto and through the housing construction.

Preferably, the coalescer filter has an upstream surface area of no morethan 25% of an upstream surface area of the second filter. In certainpreferred embodiments, the coalescer filter has an upstream surface areaof about 0.1%-10%, typically about 0.5-1%, and preferably about 0.8%, ofan upstream surface area of the second filter.

Preferably, the second filter comprises pleated media. In certainarrangements, the second filter is removable and replaceable, and thehousing is constructed and arranged with an openable end cover foraccess to remove the second filter without removal or dismounting of thecoalescer filter. The first and second filters can be mechanicallyconnected to be replaced as one unit; or, they can be separateconstructions to be replaced separately.

In one preferred embodiment, the coalescer filter comprises a non-wovenmedia of fibers having an average fiber diameter of less than 25microns, typically and preferably within the range of 9-25 microns

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an engine system using an aerosolseparator arrangement according to the present invention;

FIG. 2 is a schematic representation depicting application of principlesin a separator arrangement according to the present invention;

FIG. 3 is a perspective view of an arrangement according to the presentinvention;

FIG. 4 is a side elevational view of the arrangement shown in FIG. 3;

FIG. 5 is a cross-sectional view taken generally along line 5—5, FIG. 3,and viewed from a reverse direction to that shown in FIG. 4;

FIG. 6 is a cross-sectional view taken generally along line 6—6, FIG. 3;

FIG. 7 is an exploded cross-sectional view of the arrangement shown inFIG. 5;

FIG. 8 is a fragmentary, exploded cross-sectional view of a portion ofthe arrangement shown in FIG. 6;

FIG. 9 is an enlarged perspective view of a coalescer filter depicted inFIG. 8;

FIG. 10 is a cross-sectional view taken generally along line 10—10, FIG.7;

FIG. 11 is a top plan view of the arrangement shown in FIG. 3;

FIG. 12 is a bottom plan view of the arrangement shown in FIG. 3;

FIG. 13 is a side elevational view of the arrangement shown in FIG. 3,the view of FIG. 13 being from a side opposite to that shown in FIG. 4;

FIG. 14 is a side elevational view of the arrangement shown in FIG. 3,the view of FIG. 14 being analogous to the view of FIG. 13 with thedevice of FIG. 13 rotated 90° counterclockwise;

FIG. 15 is a view of the arrangement shown in FIGS. 13 and 14, with theview being a side elevational view depicting the device rotatedclockwise 90°, relative to the viewing angle shown in FIG. 13;

FIG. 16 is an enlarged, fragmented, cross-sectional view of a seamjoining the first and second sections, shown in FIG. 5;

FIG. 17 is a perspective view of a second embodiment of a coalescerfilter, according to the present invention;

FIG. 18 is a perspective view of the arrangement of FIG. 17 depictingthe opposite side, according to the present invention;

FIG. 19 is a top plan view of the arrangement of FIG. 18 showing ahousing body and with the cover and the first and second stage filtermedia removed, according to the present invention;

FIG. 20 is a side-elevational view of the housing body shown in FIG. 19,according to the present invention;

FIG. 21 is a cross-sectional, somewhat schematic, view taken along theline 21—21 of FIG. 19 of the body, according to the present invention;

FIG. 22 is a top plan view of the cover depicted in FIG. 18, and showingan inside surface of the cover, according to the present invention;

FIG. 23 is a top plan view of the body holding the second stage filtermedia, according to the present invention;

FIG. 24 is a top plan view of the filter body, analogous to FIG. 23, butwith the second stage filter media removed, and showing the first stagefilter media positioned in an inlet region, according to the presentinvention;

FIG. 25 is a cross-sectional, somewhat schematic, view taken along theline 25—25 of FIG. 29 of the first stage filter media, according to thepresent invention;

FIG. 26 is a fragmented, cross-sectional, somewhat schematic, view of anadapter member and depicting a bypass valve arrangement, according tothe present invention;

FIG. 27 is a schematic, side elevational, view of the second stagefilter media, according to the present invention;

FIG. 28 is a schematic view of an engine system using the filterarrangement, according to the present invention;

FIG. 29 is a top plan view of the first stage filter media construction,according to the present invention; and

FIG. 30 is a side-elevational view of the first stage filter mediaconstruction depicted in FIG. 29, according to the present invention.

DETAILED DESCRIPTION I. A Typical Application—Engine Crankcase BreatherFilter

Pressure-charged diesel engines often generate “blow-by” gases, i.e., aflow of air-fuel mixture leaking past pistons from the combustionchambers. Such “blow-by gases” generally comprise a gas phase, forexample air or combustion off gases, carrying therein: (a) oil or fuelaerosol principally comprising 0.1-5.0 micron droplets; and, (b) carboncontaminant from combustion, typically comprising carbon particles, amajority of which are about 0.1-10 microns in size. Such “blow-by gases”are generally directed outwardly from the engine block, through ablow-by vent.

Herein when the term “hydrophobic” fluids is used in reference to theentrained liquid aerosol in gas flow, reference is meant to nonaqueousfluids, especially oils. Generally such materials are immiscible inwater. Herein the term “gas” or variants thereof, used in connectionwith the carrier fluid, refers to air, combustion off gases, and othercarrier gases for the aerosol.

The gases may carry substantial amounts of other components. Suchcomponents may include, for example, copper, lead, silicone, aluminum,iron, chromium, sodium, molybdenum, tin, and other heavy metals.

Engines operating in such systems as trucks, farm machinery, boats,buses, and other systems generally comprising diesel engines, may havesignificant gas flows contaminated as described above. For example, flowrates and volumes on the order of 0-50 cfm (typically 5 to 10 cfm) arefairly common.

FIG. 1 illustrates a schematic indicating a typical system in which acoalescer/separator arrangement according to the present invention wouldbe utilized. Referring to FIG. 1, an engine is shown generally at 10.The engine 10 may generally comprise a diesel engine, although othertypes of engines are contemplated. The engine 10 gives off a blow-bygas, which may carry substantial amounts of entrained oils therein asaerosol, and also substantial amounts of fine contaminant, such ascarbon contaminants. The blow-by gasses are vented through a connector12 and through a check valve 14. The check valve 14 may also be furtherupstream in the system. Attached to the housing for the check valve 14is a connector 16. Downstream of the connector 16 and attached theretois a coalescing filter 18. The coalescing filter 18 separates theblow-by gas into two components including a liquid component and apartially filtered gas component. A second stage filter 20 is attachedto the coalescing filter 18 by way of another connector 22. The secondstage filter 20 acts to further purify the somewhat filtered gascomponent from the coalescer filter. That is, it removes fine particleswhich may still be remaining in the gas component. The purified gas isthen directed through a connector 24 through a pressure regulator 26 andinto an engine intake system 28, such as a turbo. The liquid componentfrom the coalescer filter 18 is directed through a line 30 and into anengine sump 32.

According to the present invention, an arrangement for separating ahydrophobic liquid phase from a gaseous stream (sometimes referred toherein as a coalescer/separator arrangement) is provided. In operation,a contaminated gas flow is directed into the coalescer/separatorarrangement. Within the arrangement, the fine oil phase or aerosol phase(i.e., hydrophobic phase) coalesces. The arrangement is constructed sothat as the hydrophobic phase coalesces into droplets, it will drain asa liquid such that it can readily be collected and removed from thesystem. With preferred arrangements as described hereinbelow, thecoalescer or coalescer/separator, especially with the oil phase in partloaded thereon, operates as a prefilter for carbon contaminant carriedin the gas stream. Indeed, in preferred systems, as the oil is drainedfrom the system, it will provide some self-cleaning of the coalescerbecause the oil will carry therein a portion of the trapped carboncontaminant. In preferred arrangements according to the presentinvention, the coalescer/separator arrangement is constructed with aremovable media component, for ease of cleaning or regeneration. In somepreferred systems at least a single downstream (or second) filter orpolish filter is provided. In other systems, multiple downstream filterscan be provided.

The general principles of operation, of a system according to thepresent invention, will be understood by reference to the schematic ofFIG. 2. In FIG. 2, a gas flow to be filtered is shown directed into thesystem 49 at 50. A coalescer or coalescer/filter is indicated generallyat 51. As the air passes through coalescer 51, two material streams aregenerated: a somewhat filtered or purified gas stream 52; and, a liquidphase 53. The gas stream 52 is shown directed into a second stage filter55 for polishing, with gas outflow from the arrangement indicated vialine 56. At this point, the gas may be directed to downstream equipmentor to the atmosphere. In typical systems such as those shown in FIG. 1,the gases in line 56 would be directed to an engine intake system. Inother typical systems, the gases in line 56 would be directed to theatmosphere or exhaust.

The liquid phase (with any entrained solids) from coalescer 51 is showndirected via line 53 to a drain construction 59. The material is thendirected via line 60 wherever desired. For example, it may be recycledto the crankcase to be reused. Alternatively, it may be collectedseparately for disposal.

In general, coalescer 51 comprises material in which the fine oildroplets carried within air 50 will tend to collect and coalesce intodroplets. Useful materials and constructions for this are describedbelow.

In general, preferably the support or substrate material in coalescer 51is selected and configured in a manner such that the combination ofcoalescer 51 and collected oil droplet phase will operate as a prefilterfor contaminants (especially carbon particles) also carried in line 50.The contaminants or carbon particles will tend to become entrained inthe liquid flow, leaving the system through line 53. Thus, to someextent, in a system such as that described herein, coalescer 51 isself-cleaning. Alternately stated, the continuously collected oil phasewill tend to wash some of the continuously collected carbon particlephase out of coalescer 51.

For typical systems, it is anticipated that the coalescer 51 will bedesigned such that with a typical gas flow therethrough, a substantiallife for the coalescer 51 will, in part, result from the washing effect.However, it is also anticipated that the system will not be “tuned” withan effort toward optimal operation through self-cleaning. That is, it isanticipated that coalescer 51 will, in preferred systems, be configuredfor periodic regeneration resulting from removal of filter media orcoalescing material positioned therein and either cleaning orreplacement. Alternately phrased, it is foreseen that in typicalapplications the material (media) of the coalescer will be chosen with afocus on achievement of high-efficiency aerosol removal, preferably atleast 20%, more preferably at least 25-50%, by weight in typical use.This will also result in substantial carbon-particle removal. The carbonparticle removal will in part be facilitated by the fact thatsubstantial amounts of oil phase will coalesce within the media, and theoil phase will help trap the carbon material. It is foreseen that if thecoalescer material is selected (tuned) to achieve highest efficiencycarbon particle removal, especially on the order of about 60%, it mightoffer too great a restriction to gas flow, to be fully desirable as acoalescer filter.

II. An Example of a Multi-Stage Oil Aerosol Separator

Attention is now directed to FIGS. 3-15, in which a multi-stage oilaerosol separator or coalescer/separator according to the presentinvention is provided. The system is generally referenced herein as“multi-stage” because it not only includes an aerosol separator/filterarrangement according to the present invention; but, it also includes atleast a single, and could include multiple, downstream or second stagefilters, for further purification of the air stream. Oil separator orcoalescer/separator arrangements as generally described herein may,alternatively, be utilized in overall assemblies that do not includedownstream filters.

In FIG. 3, a perspective view of a dual-stage aerosol separator assembly75 is provided. In general, the first stage of separation, whichincludes a coalescer filter, is indicated generally at 76; and, thesecond stage, which comprises a polishing filter, is located within theportion of the assembly indicated generally at 77.

Referring to FIG. 3, the assembly 75 includes a housing 80 having aninlet tube construction 81; a canister portion 82; and, an outlet tubeconstruction 83. In use, gas flow to be modified is directed into thecanister portion 82 via inlet tube construction 81. Liquid whichcoalesces within the first stage 76 drains to a bottom portion 85 of thecanister portion 82, from which it is removed as described below. Thegas phase is directed through canister portion 82, and a filter elementpositioned therein, and is directed outwardly from the assembly 78through outlet tube construction 83.

For the assembly 75 shown, the inlet tube construction 81 comprises asegmented tube construction 88 (FIG. 8). The term “segmented tubeconstruction” and variants thereof used herein, refers to a tube whichcomprises at least two separable segments mechanically secured together.That is, the segments can be readily separated from one another. In theinstance of segmented tube construction 88, two segments are showncomprising a first segment 90 and a second segment 91. Segment 91 iscompletely separable from a remainder of the assembly 75, whereassegment 90 is integrally formed with a portion of the housing 80. In thearrangement shown, the first stage coalescer separator or filter ispositioned between first segment 90 and second segment 91. Secondsegment 91 is secured, in fluid flow relation, to first segment 90, byclamp arrangement 95. Clamp arrangement 95 comprises oversleeve 96,secured to join, in a sealing manner, segments 90 and 91, by clamps 97and 98. Clamps 97, 98 include bands 102, 103 mounted around oversleeve96 and secured with fasteners 137, 138. Thus, second segment 90 can beremoved and replaced by simply loosening clamp 98.

Still referring to FIG. 3, housing 80 comprises a first or cover section104 and a second or bottom section 105. The two sections are joined toone another along seam 107 by clamp 108. For the arrangement shown,sections 104 and 105 can be separated from one another, selectively, bysimply loosening or releasing the clamp 108. This allows access to theinterior of housing 80, for servicing.

Still referring to FIG. 3, for the particular arrangement shown, coversection 104 is a molded plastic construction 109; and, bottom section105 is a sheet metal section 110. Although alternate arrangements arepossible, advantages from constructing the two sections 104 and 105 asdescribed will be apparent from following descriptions.

In use, assembly 75 can be readily mounted to the framework of a vehicleor other equipment. A variety of mounting arrangements can be used,including mounting band arrangements or a framework with appropriateretention nuts. In some instances molded mounting arrangements may beconstructed to extend around the outer periphery of cover section 104,to allow for greater choice of radial positioning, during mounting.

Before detailed description of internal components of assembly 75 ispresented, a review of certain other Figs. will be made in order toexamine outwardly viewable features of the assembly 75.

Referring first to FIG. 4, it is noted that second or bottom section 105has a bowl or funnel-shaped lower end or end cover 120 with centrallypositioned liquid drain 121 therein. The combination of bowl 120 anddrain 121 comprises a collection and drain arrangement for hydrophobicliquid. In use, as liquid coalesces within the assembly 75, it willdrain downwardly toward end plate or bowl 120, and will be funneled todrain 121. Typically, appropriate drain lines will be secured to drain121, to direct the collected liquid as desired, for example to an oilsump.

Also referring to FIG. 4, further detail concerning clamp 108 isviewable. The clamp 108 includes a metal band 125 having opposite endbrackets 126 and 127 thereon. Turn key 128 includes handle 129 which canbe turned, to tighten band 125 by pulling ends 126 and 127 together. Byso doing, due to the configuration of band 125 and certain componentspositioned thereon, discussed hereinbelow, housing sections 104 and 105can be sealed together.

Attention is now directed to FIGS. 11 and 12. FIG. 11 is a top plan viewof the arrangement shown in FIG. 3; and, FIG. 12 is a bottom plan viewof the arrangement.

Referring to FIGS. 11 and 12, it is noted that the inlet tubeconstruction 81 is mounted at the center of the housing 75. Housingcover section 104 has a generally circular outer wall 132. The circularouter wall defines a circular inner wall 133, FIG. 6. In general, inlettube construction 81 directs air passing therethrough, in the generaldirection indicated by phantom arrows 135, FIG. 11.

In an alternative construction, the inlet tube may be mounted with asidewall thereof generally tangential to a circular inside wall of thehousing, rather than directly toward a center point or axis. Atangential mount of the inlet tube relative to the housing will create atangential airflow path around the element.

Attention is now directed to FIG. 6. FIG. 6 is a cross-sectional viewtaken generally along line 6—6, FIG. 3. As a result of the orientationof view in FIG. 6 one views the interior construction of cover section104 and segmented tube construction 88.

Referring to FIG. 6, cover section 104 includes therein circular bafflemember 145. Baffle member 145 is positioned spaced from outer wall 133,generating cyclonic air flow passageway 146 therebetween. Outlet tube 83includes an extension 147 concentricity aligned with baffle member 145,and circumscribed thereby. As will be understood from descriptionshereinbelow, between section 147 and baffle member 145, an end of afilter element (described in connection with FIG. 5) will typically bepositioned in use. Typically baffle member 145 will be a length of about75%-125%, more typically about 110%, of the diameter of the inlet.

Still referring to FIG. 6, structures 150 comprise vanes in bottomsection 105, discussed below.

Still referring to FIG. 6, for the particular arrangement shown,sandwiched between second section 91 and first section 90 of segmentedtube construction 88 includes coalescer filter 150 therein. Coalescerfilter 150 is secured within framework 151 tangentially across gas flowpassageway 152. Thus, gas that is passing from region 153 of tube 90into region 154, of tube 91, generally passes through coalescer filter150. Of course coalescer filter 150 could be positioned in other partsof the assembly 75; for example in tube section 91 or in cover 104.However, the arrangement shown is convenient and effective.

Coalescer filter 150 comprises a material appropriate for coalescinghydrophobic aerosol carried within a gas stream passing through tube 91into housing 80. Preferred materials for coalescer filter 150 will bedescribed below. It is foreseen that in typical embodiments coalescerfilter 150 will comprise a nonwoven fibrous bundle.

Attention is now directed to FIG. 8. At 160 is a removable andreplaceable segment 160. Segment 160 includes appropriate framework 161,162 to receive, securely, coalescer filter 150 therein and to positioncoalescer filter 150 in securing relation between first section 90 andsecond section 91. Coalescer filter 150 is preferably sealed within theframework 161, 162. The sealing may be accomplished by gluing, crimping,heatstaking, ultrasonic welding, or by other methods and materials.Preferred constructions are as described below.

It is noted that for the arrangement shown in FIG. 8, flow passageway153 is of about an equal cross-sectional diameter to the cross-sectionaldiameter of region 154. In general, it is desirable to maintain a facevelocity of about 200-500 ft/min, preferably, about 350 ft/min acrosscoalescer 150.

Attention is now directed to FIG. 9 in which an enlarged perspectiveview of coalescer filter 150 within its framework 161, 162 is depicted.Referring to FIG. 9, the coalescer segment 160 is generallycylindrically shaped. It includes an upstream face 155, and a downstreamface 156 at an opposite side thereon.

Referring to FIG. 6, in use, as gas flow is directed through coalescerfilter 150 from region 153 toward region 154 (and housing 80),hydrophobic liquid carried or entrained within the gas flow, as anaerosol, will coalesce within the filter 150. As the liquid dropletsform, they will drain from filter 150 and, due to the gas flow, willgenerally flow outwardly from filter 150 in the direction indicated byarrows 179. The gas flow will generally cause the liquid flow to enterthe housing 80 and to drain downwardly along inward wall 133 toward aninterior of bottom cover 105. Eventually the liquid will drain to thebottom of cover 105, along end plate 120 toward drain 121, FIG. 4. Thisliquid flow will include therein some particulate material, for example,carbon particles, trapped within a liquid in coalescer 150. Thus theliquid flow will, to some extent, self-clean filter 150.

The gas flow, on the other hand, will enter housing 80 in a cyclonicpattern, between baffle 145 and inner wall 133. This gas flow is thendirected to a second stage filter, described below in connection withFIGS. 5 and 7.

Referring to FIG. 5, assembly 75 is shown in cross-section. It can beseen from FIG. 5 that assembly 75 includes a downstream or second stagefilter element 170 positioned therein. Preferably element 170 isremovable and replaceable. Element 170 generally comprises filter media171 positioned between inner and outer liners 172 and 173. A preferredconstruction, and materials, are described below. Element 170 includes aclosed end cap 174 and an open end cap 175. Open end cap 175 includes aradial sealing portion 176 sized and configured to sealingly engage tubesection 147, in a radially sealing manner therealong. As a result,material in region 176 becomes compressed between tube 147 and otherportions of element 171, to form the radial seal.

In use, after gas flow enters cyclonic section 143, it passes downwardlyin the general direction indicated by arrows 176, 177 through filterelement 170, and outwardly through outlet tube 83. Filter element 170generally operates as a polishing filter to remove such materials assome aerosol that may get past the coalescer, smoke, and hydrocarbons,from the gas flow stream.

Coalesced liquid flow, from the coalescer 150, again, will generally rundownwardly along inner wall 133 into section 105, and downwardly alongwall surface 183, toward drain 121. Thus, this liquid will generally notbe directed into filter element 170.

Attention is now directed to FIG. 10. FIG. 10 is a cross-sectional viewtaken generally along line 10—10, FIG. 5. From comparison of FIGS. 5 and10, one can understand that section 105 includes bottom vanes 185therein. For the arrangement shown, a plurality (four) vanes 185 aredepicted. The vanes 185 meet over drain 121 and provide a reinforcingstructure in bottom 120 to lightly support filter element 170 incompression against surface 186 and above liquid (which may pool on topof end cover 120, during use). In general, vanes 185 separate the filterelement 170 from the oil being collected. The vanes 185 also help toforce the element 170 into position in the housing and maintain the seal176 in place. Vanes 185 also help to ensure that the element 170 doesnot fall out of the housing during use due to vibration. In theillustrated embodiment, vanes 185 are molded separately as a separatepiece from the housing, and then connected to the housing by anappropriate fastener 122.

Attention is now directed to FIGS. 7 and 16. Cover 104 includes bottomflange 189 with gasket recess 190 therein. Gasket recess 190 is sizedand configured to receive, partially set therein, o-ring 191. Section105 includes mating flange 193. When the arrangement is assembled,flange 193 is compressed toward flange 189, with o-ring 191 positionedtherebetween. The shape of inner surface 197 of band 195 is configuredso that as key 128 is tightened, band 195 compresses flanges 189 and 193together, around o-ring 191, to cause a good seal. To facilitate this,inner surface 197 is a generally shaped like a wave or omega. FIG. 16shows the flanges 189, 193 clamped together by band 195.

For the particular preferred arrangement shown, it is noted that theupstream surface area of coalescer filter 150 is substantially smallerthan an upstream surface area of second stage filter element 170.

Especially if a fluted media is used for media 171, this difference maybe substantial. It is foreseen that using the preferred materialsdescribed herein, a system in which the coalescer filter 150 has anupstream surface of about 1-20%, and no more than 25%, of the downstreamarea of the media 171 will be effective.

Herein the term “gas flow direction arrangement” or variants thereofwill sometimes be used to refer to the portions of arrangements whichdirect gas flow. For arrangement 75, FIGS. 3-15, this would include theinlet tube, walls, baffles and outlet tube. The “gas flow directionarrangement” generally operates to ensure proper gas flow, through thefilters, in proper order.

Constructions according to the present invention can be made rathersmall, yet be highly efficient. Materials and dimensions to accomplishthis, for a variety of systems, are described below.

III. Some Useful Materials

A. Coalescer Media.

Significant advantage may be obtained by choice of certain preferredmaterial for the coalescer media. Preferred materials comprise nonwovenfibrous constructions of fibers of appropriate size, and withappropriate solidity or density, to operate as a good coalescer for thetypes of air streams likely to be encountered in use. Preferably organicfibers, such as polyester fibers, of a denier of about 1.5 or a diameterof about 9-25 micron, typically about 14.5 microns, are used to form thematerial. A preferred material is 8643 available from Kemove, Wove,Inc., Charlotte, N.C. 28241.

The density or percent solidity of the media may be varied, depending ona particular use. In general, the percent solidity, free state, is about1.5-1.8.

B. Downstream Filter Media.

For the downstream filter, conventional media used in such arrangementsas diesel engines will be acceptable for typical systems. A preferredsuch media is high surface loading pleated paper. One typical media is ahigh surface loading pleated paper having a weight of about 118+/−8lbs./3,000 square feet; a permeability of about 34+/−5.5 feet perminute; a thickness at 1.25 psi of about 0.05-0.07 inches; a tensilestrength of at least 13 pounds per inch; a wet burst strength of atleast 12 psi; and a cured wet burst strength of no greater than 40 psi.Media such as this used in an arrangement as described herein achievesan efficiency of at least 80%, by weight.

C. Other Components

Preferably, the cover section of the housing is constructed fromplastic, for example, a glass-filled nylon. The bottom section is sheetmetal. Alternatively, the entire housing could be constructed from allmetal or all plastic.

Preferably, the end caps are made from a polyurethane foam.Alternatively, the end caps could be metal.

IV. Principles Relating to Size of System

It is particularly advantageous that an arrangement utilizing principalsdescribed herein can be configured in a relatively small package, withhighly efficient operation. For example, it is foreseen that a systemsuch as that shown in the Figs. can be configured with an overall sizeof about 5 inches in diameter and about 12 inches in length, with anoverall operation efficiency of greater than 90% for gas flow streamssuch as diesel blow-by combustion aerosol.

A key component in such systems, of course, is the coalescer. Inparticular, the coalescer is configured to have an upstream surface areaof no more than about 20%, typically no more than about 10%, (usually0.5 to 1%) of the surface area of the downstream filtering media. Anexample of one usable coalescer filter has an upstream surface area ofabout 3.75 square inches. The overall volume is about 1.875 cubicinches, with a length of about 2.5 inches, a width of 1.5 inches, and athickness of 0.5 inches. The flow rate is typically 5-10 cfm, and theflow velocity typically about 3.2-6.4 feet per second. Media, such aspolyester fibers of a denier of about 1.5 and a diameter of about 14.5microns used in a system such as that described herein, achieves anefficiency of aerosol removal of at least 25%, by weight.

The downstream filter media, such as that illustrated at 171, may beconfigured to have a diameter of about 3.5 inches, and a length of about7 inches. The inner diameter, that is the diameter of the aperture forreceiving the outlet tube construction, is about 2 inches. The overallcylinder area is about 76 square inches, and the surface area is about390 square inches. A typical flow rate is about 5-10 cfm, and a typicalflow velocity is about 0.03-0.06 feet per second.

V. An Additional Embodiment

Attention is now directed to the additional embodiment depicted in FIGS.17-30.

Referring to FIG. 17, a coalescer filter construction is depicted atreference numeral 200. The coalescer filter construction 200 includes ahousing 203. The housing 203 depicted is generally a rectangular box,which represents a convenient shape for certain uses, as characterizedbelow. The depicted housing 203 has a two piece construction. Morespecifically, housing 203 comprises cover or door 205 mounted on body orshell section 206.

Referring to FIGS. 17 and 18, the housing 203 includes the followingthree flow ports: gas flow inlet port 210; gas flow outlet port 211;and, liquid flow outlet port or liquid drain 212. As a result, coalescerfilter construction 200 is configured according to the general schematicof FIG. 2.

Attention is now directed to FIGS. 19-21. At FIGS. 19-21, the housingbody 206 is depicted. The body 206 includes top wall 215 bottom wall216, first sidewall 217, second sidewall 218 and backwall 219. Walls215, 216, 217 and 218 extend around, and project from, a periphery ofbackwall 219, to form receptacle construction 221. In use, variousfilter arrangements described below are positioned within receptacle221.

Attention is now directed to FIGS. 17 and 19-21. From these Figs. it canbe seen that backwall 219 includes a front side 224, which forms aninterior surface of receptacle 221; and, backside 225, which forms arear, external, surface of receptacle 221.

Referring to FIGS. 17 and 19-21, the gas flow inlet port 210 ispositioned to extend into backside 225 of backwall 219. Morespecifically, the gas flow inlet port 210 is directed into receiver 228(FIG. 21).

Receiver 228 defines a volume 230 projecting outwardly from selectedportions of backside 225 of backwall 219. The volume 230 is sized forreceiving a coalescer filter 233 (FIG. 29) therein. Inlet port 210 isdirected into volume 230, in order to direct gas flow entering innercoalescer filter construction 200 through coalescer filter 233, in amanner described below.

In general, it is foreseen that pressures within interior 236 ofcoalescer filter construction 200 may, in use, be in the order of aboutunder 1 psi, typically about ⅓ psi (about 10-15 inches of water). Inaddition, due to the nature and properties of the diesel blow-by gases,a mist of entrained oils results, which may have a tendency to try toseep from filter construction 200. Thus, a good, secure constructionretaining door 205 on body 206 is used. Attention is directed to FIGS.18 and 22 with respect to this.

Referring to FIG. 22, door 205 includes hinge tab 240 and 241 formedintegrally thereon. The hinge tabs 240 and 241 are sized to be receivedwithin receivers 243 and 244 (FIG. 23) respectively, when door 205 ismounted on body 206. Receivers 243 and 244 allow tabs 240 and 241respectively to pivot, as door 205 is swung between an open and closedposition. When door 205 is in a closed position of FIGS. 17 and 18,receivers 243 and 244 secure hinge tabs 240 and 241 snugly, so thatalong edge 247 (FIG. 22) the door 205 cannot readily separate from body206 even under internal pressures of the blow-by gases on the order of0.5 to 1.0 psi. The internal pressure of the blow-by gases results inrather substantial forces on the door 205, in the order of about 10-40psi, often about 35 psi (about 3,700 Pa.).

Door 205 includes an opposite side edge 248, from edge 247. Along thisedge, door 205 includes retaining tabs 250 and 251 aligned withretaining tabs 253 and 254 respectively in body 206. Retaining tabs 250and 251 include apertures 256 and 257 respectively therein, overlyinganalogous apertures 253 a and 254 a and tabs 253 and 254 respectively.Preferably apertures include threaded metal inserts, to prevent wear andstripping of the threads. To secure door 205 closed, coalescer filterconstruction 200 includes thumb bolt 260 and 261 (FIG. 18) extendingthrough apertures 256 and 257 respectively.

After door 205 is appropriately positioned, it can be secured closed bythreading thumb bolts 260 and 261 for tabs 253 and 254 until the thumbbolts 260 and 261 bottom out.

A gas flow seal between door 205 and body 206 is provided by a gasket265, FIGS. 23 and 27, as described below.

Still referring to FIGS. 17, 19, and 20, note that bottom wall 216 ofhousing 203 is somewhat funnel shaped downwardly toward central, bottom,liquid drain 212. Also note that gas flow outlet port 211 extendsoutwardly from door 205 (FIGS. 18 and 22). Note that gas flow outwardlythrough outlet port 211 is directed generally orthogonal to thedirection of inlet flow through inlet port 210. Although alternateconstructions may be used, this is preferred for certain embodimentsbecause it is convenient and minimizes the space occupied by housing203.

In certain preferred embodiments, drain 212 includes a 1-way valve topermit the draining of liquid, but not the intake of liquid.

In reference again to FIG. 17, note that backwall 219 defines apertures301, 302, 303, 304 therein, located at each respective corner of body206. Preferably, apertures 301-304 include threaded metal inserts toprevent wear and stripping of the threads. Apertures 301-304 areprovided to allow filter construction 200 to be secured in a convenientlocation, for example, on an engine. Filter construction 200 lendsitself to be very flexible in its location. For example, housing 203 maybe remotely mounted from the engine crankcase at locations anywhere towhich a hose can be led. For example, housing 203 may be mounted on afirewall, or on a frame, and should be mounted above the oil sump.Preferably, housing 203 is mounted no more than 15 feet away from theengine.

Still in reference to FIG. 17, note that body 206 is constructed andarranged to receive an adapter construction 310. Adapter construction310 includes a filter housing 311 and a valve housing 312. Projectingoutwardly from filter housing 311 is an inlet tube 313, generallycircumscribing gas flow inlet port 210. Each of filter housings 311 and312 comprise circular members extending outwardly from a surroundingflange member 315. Adapter construction 310 is securely received by body206 and attached to backside 225 of backwall 219. Methods such asultrasonic welding secure adapter construction 310 to body 206. Valvehousing 312 is for holding a bypass valve construction 285 therein, asdescribed further below.

In general, housing 203 includes, enclosed therein, two filterconstructions: an upstream coalescer filter 233 and a downstream panelfilter 268. In some embodiments, coalescer filter 233 and panel filter268 will comprise separate pieces which are separately positioned withinhousing 203. In other embodiments, coalescer filter 233 and panel filter268 can be constructed adjoined to one another so that both are insertedand removed from housing 203 in a single, simultaneous operation. In theembodiment shown, coalescer filter 233 and panel filter 268 areseparate, independent members or constructions.

Referring to FIGS. 23 and 27, panel filter 268 comprises pleated media270, positioned in a generally rectangular configuration. Media 270 iscircumscribed by outer, rectangular gasket 265. Panel filter 268includes a front liner or screen 271. Front screen 271 is actuallypositioned on a downstream side of media 270, and helps retain a rigidmedia configuration. A variety of materials may be used for open orporous screen 271, for example, perforated metal, expanded metal orplastic constructions. In general, plastics such as glass-filled nylonwill be preferred, for reasons described below. In FIG. 23, screen 271is depicted as partially broken away from the downstream media 270. Itshould be understood that, in preferred embodiments, screen 271 extendsthe entire surface within the perimeter of gasket 265.

Gasket 265 may comprise a variety of polymeric materials moldable toform an appropriate gasket member, with media 270 potted therein. Oneuseful material is polyurethane such as that described in commonlyassigned U.S. Pat. No. 5,669,949 for end cap 3, hereby incorporated byreference. Material for gasket 265 includes the following polyurethane,processed to an end product (soft urethane foam) having an “as molded”density of 14-22 pounds per cubic foot (lbs/ft³) and which exhibits asoftness such that a 25% deflection requires about a 10 psi pressure. Insome embodiments, the “as molded” density varies from the 14-22 lbs/ ft³range. The polyurethane comprises a material made with I35453R resin andI305OU isocyanate. The materials should be mixed in a mix ratio of 100parts I35453 resin to 36.2 parts I3050U isocyanate (by weight). Thespecific gravity of the resin is 1.04 (8.7 lbs/gallon) and for theisocyanate it is 1.20 (10 lbs/gallon). The materials are typically mixedwith a high dynamic shear mixer. The component temperatures should be70-95° F. The mold temperatures should be 115-135° F.

The resin material I35453R has the following description:

(a) Average molecular weight

1) Base polyether polyol=500-5,000

2) Diols=60-10,000

3) Triols=500-15,000

(b) Average functionality

1) total system=1.5-3.2

(c) Hydroxyl number

1) total systems=100-300

(d) Catalysts

1) amine=Air Products 0.1-3.0 PPH

2) tin=Witco 0.01-0.5 PPH

(e) Surfactants

1) total system=0.1-2.0 PPH

(f) Water

1) total system=0.03-3.0 PPH

(g) Pigments/dyes

1) total system=1-5% carbon black

(h) Blowing agent

1) 0.1-6.0% HFC 134A.

The I3050U isocyanate description is as follows:

(a) NCO content—22.4-23.4 wt%

(b) Viscosity, cps at 25° C.=600-800

(c) Density=1.21 g/cm³ at 25° C.

(d) Initial boiling pt.—190° C. at 5 mm Hg

(e) Vapor pressure=0.0002 Hg at 25° C.

(f) Appearance—colorless liquid

(g) Flash point (Densky-Martins closed cup)=200° C.

The materials I35453R and I3050U are available from BASF Corporation,Wyandotte, Mich. 48192.

Preferably, body 206 includes perimeter trough 272 therein (FIG. 19),sized and configured to receive gasket 265. FIG. 23 shows panel filter268 seated within trough 272 and held by body 206. FIG. 23 representsthe view seen when door 205 is opened from body 206. Sealing is providedbetween door 205 and body 206 by compressing gasket 265 into perimetertrough 272 as the door 205 is closed.

In FIG. 23, panel filter 268 is illustrated as having optional handlestructure to assist in removing panel filter 268 from trough 272 in body206. In the particular example illustrated, handle structure includes apair of handles or pull tabs 278, 279. Pull tabs 278, 279 are attachedto screen 271 and may pivot between a collapsed position adjacent to thescreen 271 and an upright position, in extension from the screen 271.Pull tabs 278, 279 are preferably constructed of a non-metallicmaterial, such that they are incineratable. One useful material isplastic, such as glass-filled nylon.

In other embodiments, panel filter 268 does not include handlestructure. The panel filter 268 is removable from the body 206 bygrasping the perimeter gasket 265, or screen 271, or a combination ofthe two.

In an alternate embodiment, gasket 265 may comprise a foamed silicone.Foamed silicone may be useful, in circumstances where internaltemperatures are high, such as over 210° F.

Preferably panel filter 268 is sized and configured so that longitudinalpleats 274 of media 270 extend vertically, i.e., between top wall 215and bottom wall 216, when coalescer filter construction 200 is mountedfor use. Advantages which are derived from this concern liquid flow, asdescribed below.

One material useful for media 270 is a synthetic glass fiber filtermedium, which is coated and corrugated to enhance performance in ambientair-oil mist conditions. The synthetic glass fiber filter media may becoated with a low surface energy material, such as an aliphaticfluorocarbon material, available from 3M of St. Paul, Minn. Prior tocoating and corrugating, the media has a weight of at least 80pounds/3000 sq. ft; no greater than about 88 pounds/3000 sq. ft;typically in a range from about 80-88 pounds/3000 square feet (136.8±6.5grams per square meter). The media has a thickness of 0.027±0.004 inches(0.69±0.10 millimeters); a pore size of about 41-53 microns; a resincontent of about 21-27%; a burst strength, wet off the machine of 13-23psi (124±34 kPa); a burst strength wet after 5 minutes at 300° F. of37±12 psi (255±83 kPa); a burst strength ratio of about 0.30-0.60; and apermeability of 33±6 feet per minute (10.1±1.8 meters per minute). Aftercorrugating and coating, the media has the following properties:corrugation depth of about 0.023-0.027 inches (0.58-0.69 millimeters); awet tensile strength of about 6-10 pounds per inch (3.6±0.91 kilogramsper inch); and a dry burst strength after corrugating of no less than 30psi (207 kPa). The pleat depth is arranged to be at least 2 inches, nogreater than about 2.5 inches, and typically about 2.31 inches from tipto the outermost region of the gasket 265. The length between the pleattip and the innermost region of gasket 265 is at least about 1.5 inches,no greater than about 2 inches, and typically about 1.8 inches. Whenpart of an arrangement such as coalescer filter construction 200, media270 has a face velocity of at least about 0.1 ft/min, no greater thanabout 5.0 ft/min, and typically in a range of about 0.1-5.0 feet perminute. Preferably, there is a face velocity of about 0.4 feet perminute.

Attention is now directed to coalescer filter 233. Coalescer filter 233comprises polyester fibrous media 322, oriented in a generally circularconfiguration. Attention is directed to FIGS. 25, 29, and 30. Media 322is held and encapsulated by a frame or housing construction 378including first and second, mating housings 324, 325. Housing 325 iscircumscribed by an outer O-ring or gasket 327. Coalescer filter 233includes a pair of supports, liners, or screens 320, 321. Screens 320,321 are positioned on both the upstream and downstream side of media322, and help retain a rigid media configuration. A variety of materialsmay be used for open or porous screens 320, 321, for example perforatedmetal, expanded metal, or non-metallic materials such as plasticconstructions. In general, non-metallic materials such as plastics,i.e., glass filled nylon, will preferred, for reasons described below.O-ring gasket 327 provides a seal between receiver 228 in body 206 andcoalescer filter 233. FIG. 24 shows coalescer filter 233 seated withinreceiver 228 and housing 311. O-ring gasket 327 is compressed betweenand against coalescer housing 325 and the wall of housing 311 to form aradial seal therebetween. In an alternate embodiment, the O-ring gasketis sealed between and against housing 325 and receiver 328. In theembodiment illustrated, housings 324, 325 are constructed of a rigid,non-metallic material, such as plastic, for example, delrin.

In an alternate embodiment, in place of mating housings 324, 325 is asingle or unitary, molded housing construction, such as a molded ringaround media 322. In that embodiment, the unitary housing constructionor ring is constructed of a compressible material, for example, foamedpolyurethane, such as the foamed polyurethane forming perimeter gasket265 of the panel filter 268 and described in U.S. Pat. No. 5,669,949 forend cap 3, which patent is hereby incorporated by reference. Thespecific polyurethane useful for the molded ring is described in detailabove, with respect to gasket 265, although the “as molded” density mayvary somewhat, in certain embodiments, from the range of 14-22 lbs/ ft³.In this alternate embodiment, a module or patch of media 322 withscreens 320, 321 on two sides encasing or encapsulating media 322 ispositioned with respect to an appropriate mold, such that thepolyurethane is molded around the module of media 322, and screens 320,321. This results in a compressible housing construction, preferablycircular in configuration, molded around, holding, and circumscribingthe combination or module of media 322, and screens 320, 321. In thisconstruction, the molded, foamed polyurethane ring around the media 322is compressible to be removably mounted within housing 311 and receiver228. The ring is then compressed between and against the wall of thereceiver 228 and the media 322, to form a radial seal therebetween.

Attention is now directed to FIG. 24. Note that media 322 is a circularpatch. It is positioned at the lowermost part of coalescer filter 233and is oriented to be at a lowermost part of window 330, formed in body206. The orientation of media 322 in this location has advantages. Forexample, coalescer filter 322 coalesces liquids, such as oil, from gasstreams coming through gas flow inlet port 210. Due to the location ofmedia 322 at its lowermost point in window 330, liquid which iscoalesced is allowed to run off of media 322 over housing 324, and intothe funnel shaped bottom wall 216 to the liquid drain 212. In FIG. 25,note the smooth shoulders 332, 333 of the housings 324, 325. This shapehelps to drain the liquids coalesced within media 322. Also, bycomparing FIGS. 19 and 24, it is readily apparent that media 322 islocated outside of the direct force of flow traveling through gas flowinlet port 210. By this arrangement, housing 324 acts as a baffle toshield media 322 from the direct force of gas flow from the inlet port210.

Coalescer filter 233 is shown in the illustrated embodiments as circularwith an eccentrically disposed circular patch of media 322. That is, thecircular patch of media 322 is positioned off-center or non-centeredwithin the housing construction 378. However, coalescer filter 233 canbe a variety of shapes and sizes. For example, housing construction 378need not be circular, but can be other configurations. Media 322 neednot be circular, but can be other shapes, such as rectangular, extendingacross the full extent of the diameter of housing construction 378.Further, media 322 need not be positioned in its eccentric location withrespect to housing construction 378. For example, media 322 can becentered within housings 324, 325. However, the particular arrangementshown in the figures is used because it is attractive, eye catching, anddistinctive.

Coalescer filter 233 is shown in top plan view in FIG. 29. The oppositeside of coalescer filter 233 is a mirror-image thereof.

One type of material useable for media 322 is a polyester, fibrousmedia. The material has an average fiber diameter of 1.5 denier (about12.5 micron), and a solidity in a free state of at least 0.85%.Typically, the free state solidity is less than about 1.05%. Typicalfree state solidities are within the range of 0.85%-1.05%. It has aweight of, typically, greater than about 3.1 ounces per square yard.Typically, it has a weight less than 3.8 ounces per square yard. Typicalweights are within the range of 3.1-3.8 ounces per square yard (105-129grams per square meter). Typically, the media has a thickness at 0.002psi compression (free thickness) of greater than about 0.32 inches.Typically, the media has a thickness at 0.002 psi compression (freethickness) of less than about 0.42 inches. Typical free thicknesses forthe media are in the range of 0.32-0.42 inches (8.1-10.7 millimeters).The media has a typical permeability of no less than about 370 feet perminute (113 meters per minute).

In general, coalescer filter construction 200 further includes bypassvalve construction 285 therein. Bypass valve construction 285 isprovided in fluid flow communication with volume 230 and interior volume336 of housing 311 at a position upstream from coalescer filter 233.This is provided by duct 287, FIGS. 17 and 26. Duct 287 is provided influid flow communication with port 288 positioned adjacent to volume 230between coalescer filter 233 and gas flow inlet port 210.

Bypass valve construction 285 further includes bypass valve receiver290, also in fluid flow communication with duct 287, via port 291. Port291 is provided on an upstream side of valve member 293. Valve member293 comprises a flexible diaphragm 294 sealed against seat 295 and heldor retained there against by spring 296 and a cup 297. A plug 338 isreceived by the receiver 290, and provides a back surface for the spring296 to compress against. Downstream side 298 of diaphragm 294 isprovided a gas flow bypass outlet 299. A hole 340 is provided throughthe adapter construction 310 (FIGS. 17 and 19). The hole 340 is inairflow communication with aperture 342 in the receiver 290. Hole 340vents to atmosphere, which is in airflow communication with aperture342. Aperture 342 provides an inlet port into volume 344 behinddiaphragm 294. Therefore, the pressure of volume 344 is at atmosphericlevels.

In ordinary use, gas flow outlet through bypass outlet 299 is blocked bydiaphragm 294, under pressure from spring 296. However, should thepressure within duct 287 exceed a designed limit, diaphragm 294 will bebiased away from seat 295 sufficiently to allow gas flow directly tobypass outlet 299 without passage through coalescer filter 233. Thus,should pressure build up sufficiently within inlet port 210, for exampleas a result of restriction due to coalescer filter 233 and/or panelfilter 268 becoming sufficiently occluded, bypass valve construction 285will protect engine seals and equipment by allowing a bypass ventingthrough bypass outlet 299.

Attention is now directed to FIG. 28. In FIG. 28 is a schematic diagramshowing one possible application of the coalescer filter construction200 of the present invention. Block 350 represents a turbocharged dieselengine. Air is taken to the engine 350 through an air filter 352. Airfilter or cleaner 352 cleans the air taken in from the atmosphere. Aturbo 354 draws the clean air from the air filter 352 and pushes it intoengine 350. While in engine 350, the air undergoes compression andcombustion by engaging with pistons and fuel. During the combustionprocess, the engine 350 gives off blow-by gases. Filter 200 is in gasflow communication with engine 350 and cleans the blow-by gases. Fromfilter 200, the air is directed through channel 356 and through apressure valve 358. From there, the air is again pulled through by theturbo 354 and into the engine 350. Regulator valve or pressure valve 358regulates the amount of pressure in the engine crankcase 350. Pressurevalve 358 opens more and more, as the pressure in the engine crankcaseincreases, in order to try to decrease the pressure to an optimal level.The pressure valve 258 closes to a smaller amount when it is desirableto increase the pressure within the engine. A check valve 360 isprovided, such that when the pressure exceeds a certain amount in theengine crankcase 350, the check valve 360 opens to the atmosphere, toprevent engine damage.

A. Example Operation

In operation, coalescer filter construction 200 works as follows.Blow-by gases from an engine crankcase are taken in through gas flowinlet port 210. The gases pass through coalescer filter 233. Coalescerfilter 233 separates liquids, with any entrained solids, from the restof the gas stream. The liquid flows off of the media 322, over thehousing 324, along the front side of the back wall 219, along the funnelshaped bottom wall 216, and down through the liquid drain 212. Thisliquid material often is oil, and may be recycled to the crankcase to bereused. The gas stream which is not coalesced by coalescer 233 continueson to the second stage filter or panel filter 268. Panel filter 268removes additional particles and solids from the gas stream. Panelfilter 268 has vertical pleats, such that particles and any furtherliquid collects or agglomerates on the pleats and falls or drains bygravity downwardly toward the drain 212. The gas then exits through gasflow outlet port 211. From there, the gases may be directed, forexample, to the turbo of an engine intake system.

Should either the coalescer filter 233 or the panel filter 268 becomeclogged or occluded, pressure will fill duct 287, which will apply forceon diaphragm 294 against spring 296. Eventually, the force will move thediaphragm away from its seat 295 and permit the gas to flow throughbypass outlet 299.

The coalescer filter and the panel filter 268 are changed out asfollows. The door 205 is removed from the body 206 by unscrewingthumbolts 260, 261. The door 205 is then pivoted by way of hinge tabs240, 241 and receivers 243, 244. The view is then as shown in FIG. 23.That is, the downstream side of the panel filter 268 is viewable. In oneembodiment, the panel filter 268 and coalescer filter 233 are separate,independent members. Therefore, the panel filter 268 is removed from thebody 206 and disposed of. This may be done, for example, by graspingpull tabs 278, 279 and pulling panel filter 268 from trough 272. Theperson changing the filters then has the view as shown in FIG. 24. Thatis, the coalescer filter 233 is sealed in place within receiver 228 andhousing 311. The coalescer filter 233 is then removed from the receiver228 and disposed of. A second, new coalescer filter is oriented withinthe housing 311 and receiver 328 as shown in FIG. 24. A gasket betweenthe coalescer filter and the receiver 228 forms a seal as the coalescerfilter is properly installed. Next, a second, new panel filter 268 isoriented within the perimeter trough 272 of the body 206. This is shownin FIG. 23. The door 205 is then pivoted on its pivot arrangementbetween the hinge tabs 240, 241 and receivers 243, 244 into a closedposition (FIGS. 17 and 18). The thumbolts 260, 261 are turned withinapertures 253 a, 254 a and tightened to form a seal with gasket member265 between door 205 and body 206.

When disposing of the coalescer filter 233 and panel filter 268,preferably these constructions consist of non-metallic material at least95% non-metallic, more preferably at least 98%, and typically 99% or100% by weight non-metallic material. When the screens 271, 320, 321 areconstructed of non-metallic materials, such as plastic, and each of thecoalescer filter 233 and panel filter 268 is completely non-metallic,the coalescer filter 233 and panel filter 268 are completelyincineratable, leaving little residue. This provides for convenient andclean disposal of coalescer filter 233 and panel filter 268, and doesnot take up land-fill space.

In an alternate embodiment, the coalescer filter 233 and panel filter268 are attached or secured to one another. In this embodiment, removingthe panel filter 268 removes the coalescer filter as well. Thecombination of the panel filter 268 and coalescer filter 233 is removedfrom body 206 and disposed of (by, for example, incineration). A second,different combination of panel filter 268 secured to coalescer filter233 is inserted or placed or installed in body 206, by orientingcoalescer filter 233 in housing 311 and receiver 228, and creating theseal therebetween. As this is done, the panel filter 268 is orientedwithin perimeter trough 272. The door 205 is closed over the body 206,and tightened against gasket member 265. This forms a seal between body206 and door 205.

B. A Specific Example

One specific example for a coalescer filter construction 200 isdescribed herein. Of course, a wide variety of arrangements anddimensions are included within the scope of the present invention.

The coalescer filter 200 is useful on a 300 horsepower Caterpillar 3406Bengine. The engine has a piston displacement of at least 14.0 liters,typically 14.6 liters with 6 cylinders. It typically takes at least 35quarts of oil, and typically about 40 quarts of oil. The engine uses aSchwitzer turbo charger.

The coalescer filter construction 200 is particularly applicable toturbo charged, diesel engines having at least 50 horse power. This wouldinclude class 2 trucks up to class 8 trucks, and higher.

Engines other than turbo charged diesel engines may have applicationsfor the coalescer filter construction 200 of the present invention. Forexample, natural gas engines or gasoline engines can also use the filterconstruction 200. In preferred applications, the coalescer filterconstruction 200 will be used for large engines, that is engines of asize class 8 or above. Typical exhaust flow rates for engines of class 8or above are at least 2000 cfm, and are typically 2000-3000 cfm. Mediumsized engines, that is engines of a class 6-8, may also be used withfilter construction 200. Medium sized engines of a class of 6-8 haveexhaust flow rates of typically at least 1000 cfm; often, no greaterthan 2000 cfm. A typical class 6-8 sized engine has an exhaust flow rateof between 1000-2000 cfm. Smaller engines in the range of the class 4-6also have applications for the filter construction 200. Typical exhaustflow rates for class 4-6 engines which the filter construction 200 maybe used are at least 1000 cfm; often, the exhaust flow rates are nogreater than 1500 cfm. A small sized engine (class 4-6) has exhaust flowrates of typically 1000-1500 cfm.

One filter construction 200 tested in accordance with the presentinvention ran for 600 hours at 87% efficiency, by weight of oil. Theconstruction 200 operated for 600 hours until the crankcase pressureincreased from 3 inches of water to 5 inches of water. That is, therewere 2 inches of water to work with.

It should be understood that the crankcase internal pressure isapplication specific. In certain applications, such as systems wherethere is not much dust or debris in the air, such as in marine systems,the crankcase may have a negative pressure (that is, about −2 to −3inches of water). In other applications, such as systems where there isan abundant amount of dust or debris in the ambient air, such asoff-road trucks or city buses, the crankcase has a positive pressure.The filter construction 200 is flexible to allow it to operate witheither positive crankcase pressures, such as those typically found inturbo charged diesel trucks or off-road vehicles, or negative pressures,such as those found in marine engines.

It will be understood that a wide variety of specific configurations andapplications are feasible, using techniques described herein. Thefollowing dimensions are typical examples. The ranges are preferredbecause they have been satisfactory to perform the job, withoutresulting in a structure larger or more expensive than necessary.Although ranges outside of those discussed below are contemplated, thefollowing are convenient and typical.

Door 205 has a width between about 6-9 inches, typically about 7 inches.It has a length of between about 8-11 inches, typically about 9.5inches. Door 205 has a depth of about 2-3 inches, typically about 2.4inches. The gas flow outlet port 211 has a diameter of about 1 inch.

The body 206 has a width of at least 6 inches, no greater than about 9inches, typically about 6-9 inches, and typically about 7 inches. It hasa length of at least about 8 inches, no greater than about 11 inches,typically about 8-11 inches, and typically about 9 inches. It has adepth of at least about 2.5 inches, no greater than about 4 inches,typically between about 2.5-4 inches, and typically about 3.2 inches.Drain 212 has a diameter of at least 0.5 inches, no greater than about 2inches, typically between about 0.5-2 inches, and typically about 1.2inches. Window 330 has a diameter of at least 2.5 inches, no greaterthan about 3 inches, typically about 2.5-3 inches, and typically about2.7 inches.

When assembled together, door 205 and body 206 have a depth of at least5 inches, no greater than 8 inches, typically between about 5-8 inches,and typically about 6.4 inches.

Panel filter 268 has a length including the gasket 265 of at least about8 inches, no greater than about 11 inches, and typically between about8-11 inches, often about 9 inches. It has a width of at least 6 inches,no greater than about 8 inches, and often about 7 inches. The pleatedfilter has at least about 40 pleats, no greater than about 70 pleats,typically about 45-60 pleats, and specifically about 52 pleats. Each ofthe pleats has a pleat depth of at least about 1.5 inches, no greaterthan about 3 inches, typically within the range of about 2.0-2.5 inches,and often about 2.3 inches. The pleat length is at least 7 inches, nogreater than 9 inches, typically within the range of about 7-8.5 inches,and often about 8.3 inches. The pleated filter 268 has a perimeter,circumferential area within a range of about at least 35 square inches,no greater than about 75 square inches, typically about 40-70 squareinches, and often about 42 square inches. The pleated media 270 has anupstream media surface at least about 10 square feet, no greater thanabout 15 square feet, typically within a range of about 10-15 squarefeet, and preferably about 12 square feet.

Coalescer filter 233 includes a housing with a circular outer diameterof at least 2 inches, no greater than about 4 inches, typically within arange of 2-4 inches, and typically about 3 inches. The thickness of thecoalescer filter 233 is at least about 0.5 inches, no greater than about1.5 inches, typically within a range of 0.5-1.5 inches, and preferablyabout 1 inch. The diameter of media 322 is at least about 1 inch, nogreater than about 2 inches, typically in a range of 1-2 inches, andtypically about 1.4 inches. The thickness across media 322 is at leastabout 0.5 inches, no greater than about 0.7 inches, and typically about0.5-0.6 inches thick. The media 322 comprises fibers having an averagefiber size of about 12.5 micron and a percent solidity, free state, ofno greater than about 1.05%. The media 322 has an upstream, exposedsurface area of at least 1 sq. in., no greater than about 2.5 sq. in.,typically about 1-2 square inches, and typically about 1.5 squareinches.

The coalescer filter 233 has an upstream media surface area at leastabout 0.4%, no greater than about 1.5%, typically within the range ofabout 0.5-1%, and typically about 0.8% of the upstream media surfacearea of the pleated media 270.

The adapter construction 310 has a distance between respective centersof the filter housing 311 and valve housing 312 of at least about 3inches, no greater than about 5 inches, typically about 3-5 inches, andtypically about 4 inches. The filter housing 311 has a diameter of about2-4 inches, typically about 3.1 inches. The valve housing 312 has adiameter of about 3-5 inches, typically 4.2 inches. The inlet port 210has a diameter of about 0.5-1.5 inches, typically about 1 inch. Thebypass valve outlet port 299 has a diameter of about 1-2 inches,typically 1.4 inches. The receiver 290 has a diameter of 4-6 inches,typically about 4.7 inches. It has an overall thickness of 0.5-1.5inches, typically about 1.1 inches. The spring 296 has a diameter ofabout 0.5-1 inches, typically about 0.8 inches. It has an axial lengthin an uncompressed state of about 0.75-1.25 inches, typically about 1.1inches. The diaphragm 294 has a diameter of about 4.5-5.25 inches,typically about 4.7 inches.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein.

We claim:
 1. An arrangement for use in separating a hydrophobic liquidaerosol phase, from a gas stream, during filtration of engine crankcasegases; said arrangement comprising: (a) a first stage coalescer filterdefining a flow passageway and including a nonwoven fibrous bundleextending across the flow passageway and having a first upstream surfacearea; and, (b) a second stage filter comprising pleated media positioneddownstream from the nonwoven fibrous bundle of the first stagecoalescer; (i) the pleated media of the second stage filter having asecond upstream surface area; (ii) the first upstream surface area beingno more than 1.5% of the second upstream surface area.
 2. An arrangementaccording to claim 1 wherein: (a) the first upstream surface area iswithin the range of 0.5%-1% of the second upstream surface area.
 3. Anarrangement according to claim 1 wherein: (a) the nonwoven fibrousbundle of the first stage coalescer filter has an average fiber diameterwithin the range of 9-25 microns.
 4. An arrangement according to claim 1wherein: (a) the pleated media comprises a synthetic glass fiber filtermedia.
 5. An arrangement according to claim 1 wherein: (a) the nonwovenfibrous bundle of the first stage coalescer filter is secured between anupstream open screen and a downstream open screen.
 6. An arrangementaccording to claim 1 wherein: (a) the nonwoven fibrous bundle of thefirst stage coalescer filter has an upstream exposed surface area of nomore than 2.5 sq. in.
 7. An arrangement according to claim 1 wherein:(a) the nonwoven fibrous bundle of the first stage coalescer filtercomprises a media having a permeability of no less than 113 meters perminute.
 8. An arrangement according to claim 1 wherein: (a) the nonwovenfibrous bundle of the first stage coalescer filter has a thickness of nogreater than 0.7 inches.
 9. An arrangement according to claim 1 wherein:(a) the first stage coalescer filter and the second stage filtercomprise at least 98%, by weight, non-metallic material.
 10. Anarrangement according to claim 1 wherein: (a) the nonwoven fibrousbundle of the first stage coalescer filter: (i) is secured betweenupstream and downstream porous screens; (ii) has a circular upstreamexposed surface; (iii) has a circular downstream exposed surface; (b)the second stage filter comprises glass fiber filter media; and (c) thefirst upstream surface area is within the range of 0.5%-1% of the secondupstream surface area.
 11. An arrangement according to claim 10 wherein:(a) the first stage coalescer filter and the second stage pleated filterare secured to one another.
 12. An arrangement according to claim 1wherein: (a) said pleated media of the second stage filter is configuredin a cylinder.
 13. An arrangement according to claim 1 furtherincluding: (a) a housing construction defining an interior and having agas flow inlet and a gas flow outlet; (i) said first stage coalescerfilter and said second stage filter element being operably positionedwithin said housing interior.
 14. An arrangement according to claim 13further including: (a) a liquid collection arrangement oriented toreceive liquid collected in said first stage coalescer filter; (b) aliquid drain in fluid flow communication with said liquid collectionarrangement to drain collected liquid from said housing constructioninterior; and wherein, (c) said first stage coalescer filter and saidsecond stage filter are non-permanently positioned in said housingconstruction interior to be removable from, and to be replaceable in,said housing construction interior.
 15. An arrangement according toclaim 14 wherein: (a) said coalescer filter includes a circular outerperiphery having a seal member positioned there along; (i) the sealmember being positioned to create a seal with the housing construction,when the coalescer filter is operably positioned in the housing.
 16. Anarrangement according to claim 1 wherein: (a) said second stage filtercomprises a panel filter construction.
 17. An arrangement according toclaim 16 wherein: (a) said panel filter construction is a replacementpanel filter construction comprising: (i) an outer perimeter; (ii) aglass fiber filter media coated with an aliphatic fluorocarbon material;(iii) at least 40 pleats; each of said pleats having a pleat depth of atleast 2 inches; and (iv) an area within said outer perimeter of at least35 square inches; (b) an outer gasket member along said outer perimetercomprising a polymeric material; and (c) a media screen positioned incovering relation to said pleated media.
 18. A method of treating enginecrankcase gases; the method comprising steps of: (a) directing gasesfrom a crankcase of an engine to a first stage coalescer filter; (i) thefirst stage coalescer filter including a nonwoven fibrous bundle havinga first upstream surface area; (b) removing at least a portion of anaerosol phase, from the gases, within the coalescer filter, as acollected liquid; (c) after said step of removing at least a portion ofan aerosol phase, directing the gases to a pleated media filter; (i) thepleated media filter having a second upstream surface area; (ii) thefirst upstream surface area being no more than 1.5% of the secondupstream surface area; and (d) filtering at least a portion ofmaterials, from the gases, with the pleated media filter.
 19. A methodaccording to claim 18 including: (a) after said step of filteringmaterials with the pleated media filter, directing the gases into anengine air intake system.
 20. A method according to claim 18 wherein:(a) said step of directing the gases to a pleated media filter includesdirecting the gases to a pleated media filter that has a second upstreamsurface area; the first upstream surface area being no more than 0.5%-1%of the second upstream surface area.